We've been cd'ing since November, using medium pockets exclusively, and until a couple of weeks ago we'd had maybe 3 leaks, ever.

No longer. She's leaking all the time! OY! It's happening with both the fb's and the fuzzi fannies, mostly out of the leg holes. I don't know what to do! I'm assuming it's because she's grown a little and the sizing isn't right anymore, but larges would still be way too big on her. (She's got chubby thighs, but everything else about her is tiny!)

What should I do?!! I've thought about going to snap-ez skinny larges, but I don't like how the PUL on those is turned into the leg. I'm afraid that she'll get red marks. Plus, what a pain to change over my entire stash!

The good news is, your stash has a good resale value! I know what you mean, though, my dd's fb don't fit snugly around her thighs anymore; there's always a gap. Fortunately, she's not a heavy wetter, so I haven't had much leakage at all.
Anyway, I don't really have any good advice. Maybe she'll plump up again and they will fit her better?

I am also going to attach a letter I recieved from the Fuzzi Bunz lady when I wrote her about my diapers leaking.

Here were her reasons they could be repelling:

If you dry the diapers in the dryer, it is possible that the dryer sheets over time could cause a problem. Here is what happens...the ingredients from the dryer sheet gets in the dryer drum. When you dry your diapers they can become coated causing repelling. Once we get your diapers fixed, try hang drying them for a while. If no problems then start back drying them in the dryer and if the problem redevelops it is more than likely the dryer sheets.

I forgot to ask about your wipes solution. Do you use disposable wipes or cloth wipes with a solution. If you use a solution is it particularly oily? If so, cut out the oil from the solution for a while to see if that helps.

The harder the water the more detergent you use. The softer the water the less detergent you use. You don't seem to be using alot of detergent (I was using 2 TBS of Tide) but I would try to cut it down a little and see what happens (since you don't think your water is hard). Often repelling problems result from too much detergent. If you notice a smell then go back to the amount you were using. I'm assuming you use plain Tide. This is usually a pretty troublefree detergent. As a last resort you can try switching to a low sudsing detergent like Allen's Naturally, ECOS free and Clear, Method (found at Target) has a Free and Clear that is also low sudsing.

Make sure you are doing a double rinse. I recommend a cold prewash, a hot wash, and 2 rinses. Do fill up your washers tub instead of trying to conserve water by using the minimum amount if you washer does this. You may need more water in your washing routine.

Here is how she recommended to fix them:

Now, to fix the diapers...

Lots and lots of hot washes without detergent is best. If you stay at home just wash after wash all day. This gets out any detergent buildup.

Adding a squirt of good DISHwashing detergent (like Dawn or Palmolive) to the wash has proven effective to removing oils, detergent build-up and fabric softener. I'd do this a couple of time regardless of whether you use the oils in the wipes solution. It won't hurt anything. Do this the first two washes and then follow that with lots of hot washes as noted above. I personally do this as maintenance at least once a week. Don't use a lot or you will suds up your washer.

If these things do not work or you prefer to do this first, you can wash the diapers in the sink -- rub the fleece gently and use the dishwashing soap. Make sure to rinse thoroughly. Then wash again several times on hot without laundry detergent.

I hope this helps in some way, I know it is so frustrating when this happens I almost gave up on cloth.